The present disclosure relates generally to information handling systems, and more particularly to battery packs commonly used to provide power to portable information handling system components such as notebook computers, personal digital assistants (PDA's), cellular phones and gaming/entertainment devices.
As the value and use of information continues to increase, individuals and businesses seek additional ways to acquire, process and store information. One option available to users is information handling systems. An information handling system (‘IHS’) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
A battery converts chemical energy within its material constituents into electrical energy in the process of discharging. A rechargeable battery is generally returned to its original charged state (or substantially close to it) by a charger circuit, which passes an electrical current in the opposite direction to that of the discharge. Presently well known rechargeable battery technologies include Lithium Ion (LiON), Nickel Cadmium (NiCd), and Nickel Metal Hydride (NiMH). In the past, the rechargeable batteries (also known as “dumb” batteries) provided an unpredictable source of power for the portable devices, since typically, a user of the device powered by the battery had no reliable advance warning that the energy supplied by the rechargeable battery was about to run out.
Today, through the development of “smart” or “intelligent” battery packs, batteries have become a more reliable source of power by providing information to the IHS and eventually to a user as to the relative state of charge (RSOC), as well as a wealth of other information. Such a battery is typically equipped with electronic circuitry to monitor and control its operation. The electronic circuitry may include semiconductor chips such as microprocessors, application specific integrated circuits (ASIC's), programmable devices, and/or component based circuits.
The information is typically communicated to the IHS using a communications bus. Examples of busses may include the well-known System Management Bus (SMBus), I2C bus, parallel bus, serial peripheral interface bus, universal serial bus and the like. Information pertaining to the battery being communicated via the communications bus connection may include data elements such as battery status, manufacturer name, serial and model number, voltage, current, temperature and charge status.
In contemporary portable IHS's it is common for the IHS to be supplied DC power by a battery pack. A battery pack 100, such as shown in FIG. 1, is connected to a battery charger/battery discharge circuit 110 of an IHS (not shown), which fulfills the dual functions of supplying DC power to the IHS and charging the battery's cell stack. Battery packs typically include a controller 120 that monitors for fault conditions. The controller 120 may also be referred to as a battery management unit (BMU). When the controller 120 detects an existence of a fault condition, a fuse 180 in the battery pack 100 is blown to prevent additional damage to the IHS.
In the conventional battery pack 100 shown in FIG. 1, the controller 120 controls a charging field effect transistor, C FET 140, and a discharge field effect transistor, D FET 150, both of which are situated in series in the positive line 155 of the battery pack 100. The C FET 140 and D FET 150 control the charging and discharging of a cell stack 105 included in the battery pack 100. A sense resistor 160 is situated in the negative line 170 of the battery pack 100. A protective fuse 180, which is typically controlled by the controller 120, is included to protect the portable IHS and the battery pack 100 from damage due to excessive current. If the controller 120 detects abnormally high current across the sense resistor 160, then the controller 120 opens the C FET 140 and the D FET 150. If the controller 120 continues to sense an abnormally high current through the sense resistor 160, then the controller 120 blows the fuse 180. The battery pack 100 is disabled and may not be revived.
While the approach described above does protect the IHS, it has been found that undesired noise, such as electromagnetic interference (EMI) and/or radio frequency interference (RFI) sources and/or other nearby noise generating sources, can prematurely cause the controller 120 to blow the fuse 180. This can occur by such noise entering the battery pack 100 on the negative line 170. For example, if the controller 120 detects an abnormally high current in the sense resistor 160, the controller 120 opens the C FET 140 and D FET 150. If noise enters the negative line 170 of the battery pack 100, the controller 120 may continue to see an abnormally high sense current, and in response, the controller 120 blows the fuse 180. In this scenario, the cell stack 105 is operational, and yet due to noise being interpreted as abnormally high sense current, the battery pack 100 is permanently disabled. The customer may be inconvenienced by having to return the battery pack 100, with a fully operational cell stack 105, to the manufacturer for a replacement. Obviously, processing returns for battery packs having an operational cell stack 105 increases costs to manufacturers and decreases customer satisfaction.
Therefore, a need exists to provide a method and system for recovering from transient (or non-permanent) abnormal operating conditions in a battery pack. Additionally, a need exists to isolate the battery pack from the IHS while determining the cause of the abnormal operating conditions. Accordingly, it would be desirable to provide a method for recovery from transient (or non-permanent) abnormal operating conditions in a battery pack included in an information handling system absent the disadvantages found in the prior methods discussed above.